THE WATT AND Till-: TIJKVITIIIOK KN<ilNKS. Hi.'! 



as to the coals consumed, compared with the consumption by 

 tin- boilers previously in use here. 



" George Kow, now about seventy-two years old, and working 

 at Cam borne Yean Mine, says he assisted to build the two first 

 cylindrical boilers with internal tubes used in Cornwall. They 

 were built in Dolcoath Mine in the year 1811 ; they were 18 feet 

 long, 5 feet diameter, having an oval tube 3 feet 4 inches in the 

 largest diameter at the fire end ; the other or chimney end of 

 the tube was somewhat smaller. They were found too small for 

 the work to be done, and another boiler was built immediately, 

 22 feet long, 6 feet 2 inches diameter, and he believed a 4-feet 

 tube. 



" John Bryant, now seventy-four years old, works a steam-engine 

 at West Wheal Francis. He worked at Dolcoath the 63-inch 

 cylinder double-acting engine, upon Boulton and Watt's plan. 

 When he first worked her she had the old bee-but boiler, 

 24 feet in diameter. They were taken out for the Boulton and 

 Watt waggon boiler, 22 feet long and 8 feet wide, with two fire- 

 doors opposite one another. 



" Then the Boulton and W^att waggon was taken out for 

 Captain Trevithick's boilers, which he worked for several years. 

 Two boilers were put in, each 18 feet long, 5 feet diameter, 

 with an internal oval tube, he thinks, 3 feet by 2 feet 6 inches. 

 Shortly after, another boiler of similar form was added, 22 feet 

 long, 6 feet diameter, 4-feet tube. 



" He cannot say what the saving of coal was, but remembers 

 that the duty performed by the engine with the waggon boiler 

 was thirteen to fourteen millions. Mr. William West canie to 

 the mine as an engineer, and by paying great attention increased 

 the duty of the Boulton and Watt engine and boiler to about 

 fifteen millions. He does not recollect the duty the engine 

 performed with the cylindrical boilers. 



" Mr. Thomas Lean, of Praze, the present reporter of mine 

 engines in the western part of Cornwall, in answer to a note 

 I sent to him, says he has no account of any report of Dolcoath 

 engines for the year 1812, but during the month of April in 

 that year the engines did 21J millions. During the whole 

 of 1813 that engine was reported to average a duty of twenty-one 



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